The s-Wave of the Multifocal Electroretinogram in Cats

Miyamoto, Hiroyuki; Tazawa, Yutaka; Hayasaka, Akira; Nitta, Junfuku; Egawa, Isao; Kurosaka, Daijiro

doi:10.1007/s10384-006-0345-x

Cited by 3 publications

(4 citation statements)

References 14 publications

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“…The pig retina is rich in cones [24] with a cone:rod ratio similar to that found in the central human retina [25] and the visual streak contains no major vessels [23]. Examination of retinal electrophysiological function with multifocal electroretinography (mfERG) is well validated in porcine models [22,[25][26][27][28][29][30][31]. In pigs, short-term RD obtained with ringer lactate reattaches within 1 week and leaves the mfERG unaffected if 6 weeks restitution is allowed [22].…”

Section: Introductionmentioning

confidence: 99%

The effect of subretinal viscoelastics on the porcine retinal function

Sørensen

Ejstrup

Svahn

et al. 2011

Graefes Arch Clin Exp Ophthalmol

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The functional consequence of long-term retinal detachment in the porcine model is examined by multifocal electroretinography (mfERG). Retinal detachment (RD) in humans leaves permanent visual impairment, despite anatomical successful reattachment surgery. To improve treatment, adjuvant pharmaceutical therapy is needed, and can only be tested in a suitable animal model. The porcine model is promising and the mfERG is well validated in this model. RD was induced in 18 pigs by vitrectomy and healon injection of various concentrations. Preoperatively and 6 weeks postoperatively eight animals were examined by mfERG. The major component P1 was analyzed statistically. Indirect ophthalmoscopy and bilateral color fundus photography (FP) were performed. Selected animals underwent high-resolution optical coherence tomography (OCT). Examination by ophthalmoscopy and FP showed that the RDs remained detached for the 6 weeks of follow-up. The P1 amplitude of the mfERG did not differ significantly between the detached areas, the surrounding attached areas, and the healthy eye (p = 0.25). Similarly, P1 implicit time did not differ between the areas (p = 0.85). The lack of functional consequences of long-term RD makes the porcine model unsuitable for examining adjuvant pharmaceutical RD treatment. Future studies should focus on foveated primates.

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Section: Introductionmentioning

confidence: 99%

The effect of subretinal viscoelastics on the porcine retinal function

Sørensen

Ejstrup

Svahn

et al. 2011

Graefes Arch Clin Exp Ophthalmol

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“…Multifocal electroretinography (mfERG), introduced by Sutter & Tran (1992), is a method mainly used to evaluate the cone response in a well-defined area of the retina (Hood 2000). It has been used in various animal studies, mostly in primates (Hood et al 2001;Fortune et al 2002;Hood et al 2002;Raz et al 2002;Rangaswamy et al 2003;Kim et al 2004;Fortune et al 2005;Kim et al 2005;Rangaswamy et al 2006), cats (Miyamoto et al 2006;Vaegan et al 2000) and rodents (Ball & Petry 2000;Seeliger et al 2003;Gjorloff et al 2006), but also in pigs (Lalonde et al 2006) without the use of retinal photo monitoring during mfERG recording, rendering an exact correlation to specific retinal changes impossible.…”

Section: Introductionmentioning

confidence: 99%

The multifocal electroretinogram (mfERG) in the pig

Kyhn

Kiilgaard

López

et al. 2007

Acta Ophthalmologica Scandinavica

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ABSTRACT.Purpose: To establish a method allowing multifocal electroretinography (mfERG) recording with simultaneous fundus monitoring on anaesthetized pigs. In addition we characterize the peaks of the porcine mfERG trace, and compare the visual streak area with the optic nerve head, a known nonresponse area. Finally we illustrate the feasibility of the method by performing mfERG after an induced laser burn in the visual streak. Methods: Fifteen pigs underwent mfERG recordings at baseline, and after 1 and 6 weeks of observation. One pig was evaluated before and after retinal diode laser treatment in the visual streak. Results: The porcine mfERG trace appears similar to the human mfERG trace, and can be described by three peaks named N1, P1 and N2. Significantly faster implicit time was found in the visual streak regarding N1 (P < 0.001) than in areas outside the visual streak. Amplitudes of all three peaks were increased in the visual streak (P < 0.005). The laser-treated area was characterized by a response similar to what is found at the location of the optic nerve head. Conclusion: Porcine mfERG is similar in appearance to the human response and can be described by the same three peaks. Significantly higher amplitudes of all three peaks are found in the visual streak when compared to the optic nerve head and inferior retina. We have detected the functional deficit caused by a laser burn at the size of 3 · 3 mm.

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“…2003; Lalonde et al. 2006; Miyamoto et al. 2006) as well as modified stimulation protocols (Fortune et al.…”

Section: Part I Contextmentioning

confidence: 99%

“…The extent of the inner retinal contributions to the mfERG trace is still a subject of investigation. The introduction of selective amacrine ⁄ ganglion cell blockers (tetrodotoxin [TTX]) Rangaswamy et al 2003;Lalonde et al 2006;Miyamoto et al 2006) as well as modified stimulation protocols (Fortune et al 2002;Palmowski et al 2002) and analysis of the second order responses (Sutter & Bearse 1999) are being scrutinized for possible answers.…”

Section: Cellular Originsmentioning

confidence: 99%

Multifocal electroretinography (mfERG) in porcine eyes: establishment, sensitivity and functional implications of induced retinal lesions

Kyhn

2007

Acta Ophthalmologica Scandinavica

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Electrophysiological methods have been practised in ophthalmology for many years. In 1992 Sutter and Tran introduced the multifocal technique, which enables the recording of electrical currents derived from very localized parts of the retina. Multifocal electroretinography (mfERG) has been used in animal studies, mostly in rodents and non‐human primates, but also in pigs. However, the latter has been performed without the use of retinal photographic monitoring during mfERG recording, thus rendering an exact correlation with specific retinal changes impossible. By modifying the experimental set‐up, as well as the settings of the mfERG software, reproducible recordings on anaesthetized pigs were obtained during continuous photographic monitoring of the fundus area. The mfERG response obtained from the porcine retina was characterized by the same three amplitude deflections as described in studies on human retinas: N1, P1 and N2. Multifocal ERG responses derived from within the visual streak of the porcine retina were characterized by significantly faster implicit times and higher amplitudes for all three peaks, compared with responses derived from within the inferior, less cone‐rich part of the retina. The spatial resolution of the developed mfERG protocol enables the detection of retinal areas of reduced functionality of a size ≥ 1.2 mm. In the acute and late phases, significant reductions in all peak amplitudes were observed after retinal laser photocoagulation. Implicit times were less influenced by the treatment. This corresponded with marked central tissue destruction found histologically. The following surgical procedures necessitate surgical access to the subretinal space: vitrectomy; retinal detachment bleb formation; retinal diathermia, and retinotomy. Extending the size of these interventions, which is necessary if subsequent surgery is to be carried out in the subretinal space, caused a statistically non‐significant tendency towards reduced amplitudes within the first postoperative week. Only retinal diathermia significantly prolonged the implicit time of one peak (N1) after 1 week of observation. The functional consequences of the surgical procedures were all found to cause reversible changes in the mfERG within a 6‐week observation period. Thus, these findings indicate that in experimental subretinal surgery on pigs, any mfERG change found 6 weeks postoperatively could be attributed to factors other than surgical access to the subretinal space. This renders the described animal model and mfERG‐protocol applicable in future experiments regarding pathology, treatment, surgery and stem cell transplantation in the retina as well as in the subretinal space of the porcine eye.

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The s-Wave of the Multifocal Electroretinogram in Cats

Abstract: The s-wave is present in the mfERG in the cat, and its loss following injections of TTX and NMDA supports the view that the s-wave reflects the function of the ganglion cells and their axons.

Cited by 3 publications

References 14 publications

The effect of subretinal viscoelastics on the porcine retinal function

The effect of subretinal viscoelastics on the porcine retinal function

The multifocal electroretinogram (mfERG) in the pig

Multifocal electroretinography (mfERG) in porcine eyes: establishment, sensitivity and functional implications of induced retinal lesions

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